1. Field of the Invention
The invention relates to a switch element for valve shut-off, fabricated as a cam follower for a plunger rod valve drive of an internal combustion engine.
2. Description of the Related Art
Such a switch element has been disclosed in DE 199 15 531 A1. A disadvantage of this is that only a one-sided coupling is provided over a piston. Therefore, there is an unnecessarily high component load to be reckoned with in the coupling area. Besides, coupling involves an undesirable tilting of the inner element relative to the outer part. At the same time, it is found that the twist safety inserted in the radial bore of the inner element is relatively costly, particularly as its pressing in leads to undesirable deformation of the radial bore, which may adversely affect a proper lengthwise motion of the piston. Since the piston with its cylindrical jacket enters a bore in the outer part for coupling, the latter undesirably has only a very small bearing area, and in this case it is necessary to work with a very fine tolerance. When the piston is not properly run out, it may also happen, owing to the geometry in the transition to the bore, that only two edges bear. Here wear must be reckoned with. Last but not least, the switch element, because of its one-sided oil supply, must be built into its guide directionally.